This study aimed to evaluate how excess selenium induces oxidative stress by determining antioxidant enzyme activity and changes in expression of selected selenoproteins in mice. BALB/c mice (n = 20 per group) were fed a diet containing 0.045 (Se-marginal), 0.1 (Se-adequate), 0.4 (Se-supernutrition), or 0.8 (Se-excess) mg Se/kg. Gene expression was quantified in RNA samples extracted from the liver, kidney, and testis by real-time quantitative reverse transcription-polymerase chain reaction. We found that glutathione peroxidase (GPx) and catalase activities decreased in livers of mice fed the marginal or excess dose of Se as compared to those in the Se-adequate group. Additionally, superoxide dismutase and glutathione reductase activities were significantly reduced only in mice fed the excess Se diet, compared to animals on the adequate Se diet. Se-supernutrition had no effect on hepatic mRNA levels of GPx isoforms 1 and 4 (GPx1 and GPx4), down-regulated GPx isoform 3 (GPx3), and upregulated selenoprotein W (SelW) mRNA expression. The excess Se diet led to decreased hepatic mRNA levels of GPx1, GPx3 and GPx4 but no change in testicular mRNA levels of GPx1, GPx3 or SelW. Dietary Se had no effect on testicular mRNA levels of GPx4. Thus, our results suggest that Se exposure can reduce hepatic antioxidant capacity and cause liver dysfunction. Dietary Se was found to differentially regulate mRNA levels of the GPx family or SelW, depending on exposure. Therefore, these genes may play a role in the toxicity associated with Se.

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This paper investigates journal bearings, and builds a lubrication model taking into account misalignment, the lubricant couple stress effect and shear thinning. In order to explore the sensitivity of couple stress fluid lubrication performance to oil film thickness, we introduce the critical oil film thickness coefficient. The results show that the sensitivity increases with the increase of the couple stress coefficient, and it is highest in the area of minimum oil film thickness. Compared with a parallel journal, increases in the misalignment angle strengthen the effect of couple stress. Shear thinning also plays an important role in bearing lubrication performance. For a low oil inlet temperature, the effect of shear thinning increases with the increase of the couple stress parameter. For a high oil inlet temperature, the influence is negligible. An increase in the misalignment angle will not further enhance the effect of shear thinning.

IntroductionCanine parvovirus type-2 (CPV-2) causes acute infectious diseases in puppies, which show high morbidity and mortality. Better effect of vaccination against these diseases could be achieved with deeper knowledge of CPV-2 genotype dissemination and mutation history. This study investigated CPV-2–positive samples collected recently over a wide region of China.Material and MethodsA total of 118 faecal samples from dogs identified as CPV-positive were collected from veterinary clinics in central and eastern China. Overall, 16 strains collected from Anhui, 29 from Henan, and 16 from Zhejiang Province were sequenced to determine the genotypic composition of CPV-2 and mutational complexity of CPV-VP2.ResultsThe CPV-2a, CPV-2b, and CPV-2c genotypes were detected in Anhui and Henan Provinces, while CPV-2c alone was detected in Zhejiang Province. Sequence analysis of all strains showed 98.5%–99.8%, 98.3%–99.9%, and 98.7%–99.8% identity among the 16 Anhui, 29 Henan, and 16 Zhejiang strains, respectively. Strains collected from Anhui and Henan Provinces showed lower identity (97.0%), suggesting greater genetic divergence in central China. The mutation rates of Henan and Anhui strains were lower than that of Zhejiang strains. Major amino acid mutations occurred at sites 5, 370, 426, and 440. Epitope and entropy analyses implied these sites’ likely conformance to the principles of mutation tendency, complexity, and diversity.ConclusionThe findings for the evolutionary structure of CPV-2 strains collected from three provinces in central and eastern China advance trend monitoring of the genetic variation in canine parvovirus and point to its implications in the development of novel vaccines.

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